The four-year-old is at the centre of a 'For Luca' campaign, which aims to raise awareness of meningitis and £1.5m for treatment by getting celebrities to write Luca's name on their hand.
Maradona posted a video with Luca's name and a number 10, his old shirt number, on his hand, and said: "Luca, as you may know I am Diego Armando Maradona. I send you a big kiss and want you to know that we are all with you. I hope that you can recover and we all ask God for that.
"I am excited because my son was just born today and he's very cute, like you. He has every right to live his life out and so do you. I love you with all my soul and ask God to protect you."
Maradona famously used his hand to score against England in the 1986 World Cup.